Epidemiology of schizophrenia

Schizophrenia affects around 0.3–0.7% of people at some point in their life,[1] or 21 million people worldwide as of 2011 (about one of every 285).[2] By using precise methods in its diagnosis and a large, representative population, schizophrenia seems to occur with relative consistency over time during the last half-century.[3]

DALY for schizophrenia per 100,000 inhabitants in 2004.
  no data
   185
  185–197
  197–207
  207–218
  218–229
  229–240
  240–251
  251–262
  262–273
  273–284
  284–295
   295

While it is claimed that schizophrenia occurs at similar rates worldwide, its prevalence and incidence varies across the world,[4] within countries,[5] and at the local and neighborhood level.[6] It causes approximately 1% of worldwide disability-adjusted life years (DALYs).[7] The rate of schizophrenia varies up to threefold depending on how it is defined.[1]

By age and gender

Schizophrenia is diagnosed 1.4 times more frequently in males than females, and typically appears earlier in men[7]—the peak ages of onset are 20–28 years for males and 26–32 years for females.[8] Onset in childhood is much rarer,[9] as is onset in middle- or old age.[10]

Generally, the mean age of first hospital admission for treatment of schizophrenia is between 25 and 35. Studies have suggested that lower income individuals tend to have their disorder diagnosed later after the onset of symptoms, relative to those of better economic standings. As a result, the lower social classes are more likely to be living with their illness untreated.[3]

It is generally accepted that women tend to present with schizophrenia anywhere between 4–10 years after their male counterparts.[11] However, using broad criteria for diagnosing schizophrenia shows that males have a bimodal age of onset, with peaks at 21.4 years and 39.2 years old, while females have a trimodal age of onset with peaks at 22.4, 36.6, and 61.5 years old.[12]

This additional post-menopausal peak of late-onset schizophrenia in women calls into question the etiology of the disease and raises a debate about "subtypes" of schizophrenia, with men and women being susceptible to different types (see Causes of Schizophrenia). This is further supported by the variability in presentation of the disease between the genders.[13]

Other theories that may explain this difference include protective or predisposing factors in men or women that may render them more (or less) susceptible to the disease at different points in life. For example, estrogen may be a protective factor for women, as estradiol has been found to be effective in treating schizophrenia when added to antipsychotic therapy.[13]

By country

In 2000, the World Health Organization found the prevalence and incidence of schizophrenia to be roughly similar around the world, with age-standardized prevalence per 100,000 ranging from 343 in Africa to 544 in Japan and Oceania for men and from 378 in Africa to 527 in Southeastern Europe for women.[14]

However, the impact of schizophrenia tends to be highest in Oceania, the Middle East, and East Asia, while the nations of Australia, Japan, the United States, and most of Europe typically have low impact. Despite relative geographical proximity, the DALY rate of schizophrenia in Indonesia nearly doubles that of Australia (the nations with the highest and lowest respective DALY rates). Discrepancies between DALY rates and prevalence may arise from differences in availability of medical treatment: years lived with mental disorders carry significantly higher DALY values when unmedicated than when medicated.[14]

The following tables record the age-standardised disability-adjusted life years rates per 100,000 inhabitants (recorded in 2004).[15]

Rank Country DALY rate
1 Indonesia321.870
2 Philippines317.079
3 Thailand315.533
4 Malaysia314.199
5 Sri Lanka312.278
6 Brunei312.101
7 Singapore311.872
8 Tuvalu287.660
9 Laos287.175
10 Uzbekistan286.942
11 Marshall Islands284.733
12 Burma281.795
13 Papua New Guinea281.681
14 Kyrgyzstan279.941
15 Iraq279.362
16 Samoa279.080
17 Palau278.983
18 Tonga278.129
19 Federated States of Micronesia277.711
20 Vanuatu277.423
21 Syria277.308
22 Niue276.384
23 Vietnam275.786
24 Lebanon275.768
25 Iran275.672
26 Solomon Islands275.561
27 Yemen275.117
28 Cambodia274.896
29 Cook Islands274.401
30 Tunisia273.845
31 Morocco273.587
32 Libya273.506
33 Egypt273.441
34 Jordan273.298
35 Cyprus273.036
36 Saudi Arabia270.202
37 Mongolia270.025
38 Oman270.003
39 Bahrain269.861
40 Armenia269.694
41 Azerbaijan269.573
42 Kuwait269.369
43 China269.146
44 North Korea269.064
45 Kiribati268.930
46 Nauru268.930
47 India268.903
48 Suriname268.690
49 Fiji268.504
50 South Korea268.395
51 Qatar267.384
52 U.A.E.267.316
53 Pakistan266.348
54 Tajikistan266.302
55 Bangladesh265.704
56   Nepal265.396
57 Bhutan264.924
58 Turkmenistan264.634
59 East Timor259.483
60 Maldives257.915
61 Uruguay257.220
62 Nicaragua256.836
63 Cuba256.254
64 Honduras256.040
65 Brazil255.328
66 Mexico254.998
67 Trinidad and Tobago254.966
68 Dominican Republic254.906
69 Grenada254.731
70 Saint Vincent and the Grenadines254.731
71 Guatemala254.603
72 El Salvador254.538
73 Saint Lucia254.249
74 Chile254.056
75 Jamaica254.052
76 Afghanistan253.778
77 Ecuador253.573
78 Colombia253.524
79 Haiti253.521
80 Venezuela253.432
81 Argentina253.404
82 Bolivia253.353
83 Bahamas253.284
84 Dominica253.184
85 Antigua and Barbuda253.183
86 Saint Kitts and Nevis253.183
87 Peru253.060
88 Panama252.960
89 Barbados252.912
90 Belize252.768
91 Costa Rica252.764
92 Guyana252.626
93 Paraguay252.615
94 Angola252.602
95 Sierra Leone250.554
96 Mali248.112
97 Albania247.412
98 Liberia247.215
99 Niger247.160
100 Equatorial Guinea247.009
101 Chad246.930
102 Guinea-Bissau246.913
103 Nigeria246.675
104 Burkina Faso246.534
105 Guinea244.827
106 Benin244.670
107 Cameroon244.614
108 Senegal244.417
109 Togo244.322
110 Gambia244.157
111 Madagascar244.013
112 Burundi242.958
113 Mauritania242.681
114 Côte d'Ivoire242.415
115 Comoros242.247
116 D.R. of the Congo241.964
117 Bosnia and Herzegovina241.524
118 Gabon241.036
119 Rwanda240.859
120 South Africa240.510
121 C.A.R.239.919
122 Algeria239.752
123 Tanzania239.346
124 Cape Verde239.200
125 Mozambique239.198
126 Bulgaria238.471
127 Ethiopia238.315
128 Zimbabwe238.167
129 Zambia238.155
130 Swaziland237.481
131 Malawi237.361
132 Romania237.228
133 Lesotho237.095
134 Uganda236.848
135 Mauritius236.587
136 Seychelles236.317
137 Georgia235.629
138 Eritrea235.605
139 Djibouti235.323
140 Kenya234.975
141 Somalia234.846
142 São Tomé and Príncipe234.730
143 Rep. of the Congo234.554
144 Botswana234.546
145 Sudan234.492
146 Serbia and Montenegro234.431
147 Macedonia234.208
148 Turkey234.024
149 Ghana234.009
150 Poland233.876
151 Slovakia233.549
152 Namibia233.280
153 Kazakhstan210.649
154 Ukraine209.780
155 Russia206.910
156 Hungary206.746
157 Belarus206.098
158 Lithuania205.798
159 Latvia203.750
160 Moldova202.684
161 Estonia201.738
162 New Zealand193.707
163 Japan193.509
164 France189.104
165  Switzerland188.713
166 Israel188.005
167 Croatia187.935
168 Finland187.699
169 Denmark187.542
170 Norway187.493
171 Slovenia187.209
172 Spain186.362
173 Netherlands186.282
174 Portugal186.253
175 Belgium186.130
176 Sweden186.011
177 Canada185.942
178 Czech Republic185.826
179 Germany185.762
180 Andorra185.725
181 United States185.629
182 Ireland185.626
183 Italy185.589
184 Luxembourg185.307
185 United Kingdom185.182
186 Austria185.116
187 Greece185.063
188 Malta184.870
189 San Marino184.854
190 Monaco184.831
191 Iceland184.830
192 Australia164.255

United States

In 2010, there were approximately 397,200 hospitalizations for schizophrenia in the United States. About 88,600 (22.3%) were readmitted within 30 days.[16]

By Race

In Western Europe it has been documented that immigrant groups are more likely to be diagnosed with schizophrenia. The immigrant groups that are predominate in the increased schizophrenia diagnosis are of black origin[17]. The highest rates of schizophrenia diagnosis come from those of Afro-caribbean ethnicity and those with black african descent[17]. In the US, African Americans have been found to be three times more likely to be diagnosed with schizophrenia, and when taking socioeconomic status into account they are two times more likely than their white counterparts[17]. However, those diagnosed with schizophrenia in developing countries have been found to have better course and outcome than their counterparts in industrialized countries[18]. These improved outcomes may be because these countries place emphasis on harmonious interpersonal relationships[18].

Prenatal Care

In two natural experiments conducted on populations that experienced famine, the rates of schizophrenia diagnosed were observed. During both the Chinese Famine (1950's) and the Dutch Hunger Winter (1944-1945) the cohorts of the exposed group were twice as likely to develop schizophrenia as compared to the unexposed cohorts[19]. It is possible that prenatal nutritional deficiency plays a role in the development of schizophrenia, in particular the lack of micronutrients. Countries with poor prenatal care, low food supply, or developing countries could have a higher incidence of schizophrenia, but more research is needed to confirm this hypothesis.

References

  1. van Os J, Kapur S. Schizophrenia. Lancet. 2009;374(9690):635–45. doi:10.1016/S0140-6736(09)60995-8. PMID 19700006.
  2. "Schizophrenia". World Health Organization. 2011. Retrieved February 27, 2011.
  3. Häfner H, an der Heiden W. Epidemiology of Schizophrenia. The Canadian Journal of Psychiatry. 1997;42:139–151. doi:10.1177/070674379704200204.
  4. Jablensky A, Sartorius N, Ernberg G, et al.. Schizophrenia: manifestations, incidence and course in different cultures. A World Health Organization ten-country study. Psychological Medicine Monograph Supplement. 1992;20:1–97. doi:10.1017/S0264180100000904. PMID 1565705.
  5. Kirkbride JB, Fearon P, Morgan C, et al.. Heterogeneity in incidence rates of schizophrenia and other psychotic syndromes: findings from the 3-center AeSOP study. Archives of General Psychiatry. 2006;63(3):250–8. doi:10.1001/archpsyc.63.3.250. PMID 16520429.
  6. Kirkbride JB, Fearon P, Morgan C, et al.. Neighbourhood variation in the incidence of psychotic disorders in Southeast London. Social Psychiatry and Psychiatric Epidemiology. 2007;42(6):438–45. doi:10.1007/s00127-007-0193-0. PMID 17473901.
  7. Picchioni MM, Murray RM. Schizophrenia. BMJ. 2007;335(7610):91–5. doi:10.1136/bmj.39227.616447.BE. PMID 17626963.
  8. Castle D, Wessely S, Der G, Murray RM. The incidence of operationally defined schizophrenia in Camberwell, 1965–84. The British Journal of Psychiatry. 1991;159:790–4. doi:10.1192/bjp.159.6.790. PMID 1790446.
  9. Kumra S, Shaw M, Merka P, Nakayama E, Augustin R. Childhood-onset schizophrenia: research update. Canadian Journal of Psychiatry. 2001;46(10):923–30. doi:10.1177/070674370104601004. PMID 11816313.
  10. Hassett, Anne M.; et al. (20 June 2005). Psychosis in the Elderly. London: Taylor & Francis. p. 6. ISBN 978-1-84184-394-0.
  11. Hafner H, Maurer K, Loffler W, et al.. The epidemiology of early schizophrenia: Influence of age and gender on onset and early course. The British Journal of Psychiatry. 1994;164(23):29–38. PMID 8037899.
  12. Castle D, Sham P, Murray R.. Differences in distribution of ages of onset in males and females with schizophrenia. Schizophrenia Research. 1998;33(3):179–183. doi:10.1016/s0920-9964(98)00070-x.
  13. Kulkarni J, Riedel A, de Castella AR, et al.. Estrogen – A potential treatment for schizophrenia. Schizophrenia Research. 2001;48(1):137–144. doi:10.1016/s0920-9964(00)00088-8. PMID 11278160.
  14. Ayuso-Mateos, Jose Luis. "Global burden of schizophrenia in the year 2000" (PDF). World Health Organization. Retrieved February 27, 2013.
  15. "Age-standardized DALYs per 100,000 by cause, and Member State, 2004". Global burden of disease: 2004 update. World Health Organization (WHO). 2004. Retrieved 2011-04-01.
  16. Elixhauser A, Steiner C. Readmissions to U.S. Hospitals by Diagnosis, 2010. HCUP Statistical Brief #153. Agency for Healthcare Research and Quality. April 2013.
  17. Bresnahan, Michaeline; Begg, Melissa D.; Brown, Alan; Schaefer, Catherine; Sohler, Nancy; Insel, Beverly; Vella, Leah; Susser, Ezra (2007-08-01). "Race and risk of schizophrenia in a US birth cohort: another example of health disparity?". International Journal of Epidemiology. 36 (4): 751–758. doi:10.1093/ije/dym041. ISSN 0300-5771.
  18. Bae, S.-W.; Brekke, J. S. (2002-01-01). "Characteristics of Korean-Americans With Schizophrenia: A Cross-Ethnic Comparison With African-Americans, Latinos, and Euro-Americans". Schizophrenia Bulletin. 28 (4): 703–717. doi:10.1093/oxfordjournals.schbul.a006974. ISSN 0586-7614.
  19. Brown, A. S.; Susser, E. S. (2008-08-20). "Prenatal Nutritional Deficiency and Risk of Adult Schizophrenia". Schizophrenia Bulletin. 34 (6): 1054–1063. doi:10.1093/schbul/sbn096. ISSN 0586-7614.


See also

References

    Further reading

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